Hugouvieux-Cotte-Pattat N, Quesneau Y, Robert-Baudouy J
J Bacteriol. 1983 May;154(2):663-8. doi: 10.1128/jb.154.2.663-668.1983.
The biochemical and physiological aspects of hexuronate transport in Erwinia carotovora were studied to approach the genetic regulation of the hexuronate degradative pathway in this bacterial species. An active transport system for glucuronate and galacturonate uptake exists in E. carotovora. The glucuronate entry reaction displayed saturation kinetics with an apparent Km of 0.05 mM (at 25 degrees C; pH 7). Galacturonate appeared to be a competitive inhibitor of glucuronate uptake with a Ki of 0.1 mM. Glucuronate permeation was not induced by glucuronate itself in wild-type strains. Galacturonate induced the uptake of glucuronate (about fivefold). The induced synthesis of the transport system was sensitive to catabolite repression by glucose. Mutants able to grow on glucuronate as the sole carbon source showed constitutive synthesis of the hexuronate transport system.
为了探究胡萝卜软腐欧文氏菌中己糖醛酸降解途径的遗传调控，对该菌中己糖醛酸转运的生化和生理方面进行了研究。胡萝卜软腐欧文氏菌中存在一个用于摄取葡萄糖醛酸和半乳糖醛酸的主动转运系统。葡萄糖醛酸的进入反应呈现出饱和动力学，在25℃、pH 7时表观Km为0.05 mM。半乳糖醛酸似乎是葡萄糖醛酸摄取的竞争性抑制剂，Ki为0.1 mM。在野生型菌株中，葡萄糖醛酸本身不会诱导葡萄糖醛酸通透。半乳糖醛酸诱导葡萄糖醛酸的摄取（约五倍）。转运系统的诱导合成对葡萄糖的分解代谢阻遏敏感。能够以葡萄糖醛酸作为唯一碳源生长的突变体显示出己糖醛酸转运系统的组成型合成。
